4 68 



THE ANIMAL PARASITES OF MAN 



It is stated that the males die after fertilizing the females, thus explaining why 

 they are so rarely met with in faeces [but it is probable that they often escape notice 

 from their small size. J. W. W. S.]. 



Development. The eggs, which often adhere together, contain a 

 tadpole-like embryo, the thin tail of which is bent upwards ventrally ; 



FIG. 345--^, 



male, and , fe- 

 male, of Oxyuris 

 vermictilaris.$li. 



FIG. 346. On the left, 

 female ; on the right, male. 

 A, anus ; M, mouth ; F, 

 vulva. Greatly enlarged. 

 (After Glaus.) 



FIG. 347-. Oxy- 

 uris vermicularis : 

 egg freshly deposited, 

 with tadpole-like 

 embryo, x 640. 



FIG. 348. Oxy- 

 uris vermicularis : 

 egg twelve hours after 

 deposition, with ne- 

 matode-like embryo, 

 x 640. 



the embryo in a short time, given a sufficiently high temperature, passes 

 into a second folded nematode-like embryonal stage, lying in the egg- 

 shell, either in the faeces, with which also numerous females pass out, 

 or in the moisture of the groove between the buttocks, and they there 

 await the opportunity of being reintroduced into man per os. It is 



